The complete Science article states that "specific components of the microbiota - the microorganisms that normally colonize the body - can affect disease progression in mouse models of arthritis, central nervous system inflammation, diabetes, intestinal inflammation, and obesity."

Also - "...Atarashi et al. demonstrate that indigenous species of Clostridium bacteria, a large component of the mammalian microbiota, promote anti-inflammatory immune responses by expanding and activating regulatory T-cells. The finding has important implications for understanding how gut-resident bacteria affect both intestinal and systemic immune responses."

It is interesting that there are many "we don't know why" statements throughout the 2-page article, but scientists' observations regarding a clear cause-and-effect of gut bacteria and health is hard to miss. T-cells are our "little soldiers," the white blood cells that "search and destroy" anything that threaten the host. I hope that this type of research will lead doctors to finally understand that a healthy gut = a healthy person, and that vomiting, diarrhea, etc. cannot possibly be trivial or a "mental problem" but something very serious and worth investigating.